IT’S hardly news that a play goes through plenty of revisions before opening night. Scenes are cut, dia logue is rewritten, characters dropped, entire acts jettisoned.

All that is to be expected with a new play.

But what of a play, written nearly 60 years ago by one of America’s foremost dramatists, that was acclaimed at its premiere and has been successfully revived countless times since?

“The Country Girl,” Clifford Odets’ riveting 1950 backstage melodrama, may not be a masterpiece, but it certainly “stands near the top of the second-rate,” as Frank Rich once wrote.

Why then are director Mike Nichols and playwright Jon Robin Baitz (co-executor of the Odets estate) butchering it as if it were a third-rate effort by a fourth-rate hack?

Their revival, starring Morgan Freeman as a washed-up alcoholic actor attempting a comeback and Frances McDormand as his long-suffering wife, is in previews.

Audience members familiar with the play surely were startled Monday to discover that an entire six-page scene was dropped from Act 1.

Audience members unfamiliar with the play must have sensed something was missing, since the first act ran a skimpy 37 minutes (with a top ticket price of $100, thank you very much).

The cut seems to have been made in haste – the Playbill for that performance still listed the scene.

And it is not superfluous. Set in a shabby apartment, it’s the first time the audience gets an extended look at the troubled relationship between the actor and his wife.

The show’s spokesman says: “As is usual in the previews, there are changes being tried out and worked on nightly to prepare for the official opening.”

But backstage sources whisper that the scene was cut, in part, because Freeman is struggling with his lines – which is ironic, since he’s playing a character who’s terrified of forgetting his lines on opening night.

After the first preview last week, Internet theater sites were buzzing that several cast members were stumbling around, unsure not only of their lines but of their blocking.

Company members rolled their eyes and bit their tongues that night when Chip Zien, playing the producer, said of the old actor: “If he spoke one line of the author’s script tonight, it never reached my ears.”

The producers of “The Country Girl” were sufficiently concerned about the state of their show that they canceled the invited dress rehearsal and, sources say, debated postponing the first preview.

In the end, though, Nichols decided the actors had to get on their feet in front of an audience.

Nichols, it’s said, generally does his best work when a show is up and running. In rehearsals, he spends more time telling jokes and swapping showbiz anecdotes than drilling the actors.

Which is why some company members think this revival looks under-rehearsed.

At the climax of the play, the director, upon learning that the old actor has tried to commit suicide, demands to see his wrists. Odets’ stage directions are explicit: Agonized, Frank slowly raises his wrists; Bernie looks down for several intense seconds and the story is plain.

But in this version, Freeman wraps his arms around himself. This causes Peter Gallagher, as Bernie, to slap his head as if he’d locked his keys in the car.

I hear this change was Freeman’s idea.

Well, it’s the kind of choice an actor makes in previews that a good director gets rid of by opening night.

“The Country Girl” has another two weeks of previews. Freeman, truly a fine actor, should grow more comfortable in the role.

And if Nichols and Baitz can pull off their version of “The Country Girl,” there’s no telling what they’ll do next.